Luteal Phase Length Research Articles

Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles

The use of apps that record detailed menstrual cycle data presents a new opportunity to study the menstrual cycle. The aim of this study is to describe menstrual cycle characteristics observed from a large database of cycles collected through an app and investigate associations of menstrual cycle characteristics with cycle length, age and body mass index (BMI). Menstrual cycle parameters, including menstruation, basal body temperature (BBT) and luteinising hormone (LH) tests as well as age and BMI were collected anonymously from real-world users of the Natural Cycles app. We analysed 612,613 ovulatory cycles with a mean length of 29.3 days from 124,648 users. The mean follicular phase length was 16.9 days (95% CI: 10–30) and mean luteal phase length was 12.4 days (95% CI: 7–17). Mean cycle length decreased by 0.18 days (95% CI: 0.17–0.18, R2 = 0.99) and mean follicular phase length decreased by 0.19 days (95% CI: 0.19–0.20, R2 = 0.99) per year of age from 25 to 45 years. Mean variation of cycle length per woman was 0.4 days or 14% higher in women with a BMI of over 35 relative to women with a BMI of 18.5–25. This analysis details variations in menstrual cycle characteristics that are not widely known yet have significant implications for health and well-being. Clinically, women who wish to plan a pregnancy need to have intercourse on their fertile days. In order to identify the fertile period it is important to track physiological parameters such as basal body temperature and not just cycle length.

Association between diminished ovarian reserve and luteal phase deficiency

To determine the association between biomarkers of ovarian reserve and luteal phase deficiency (LPD). Secondary analysis of a prospective time-to-conceive cohort study. Not applicable. Women attempting conception, aged 30-44years, without known infertility. Measurement of early follicular phase serum levels of antimüllerian hormone, FSH, inhibin B, and E2. The primary outcome was LPD, defined by luteal bleeding (LB) (≥1day of LB) or a short luteal phase length (≤11days). Overall, 755 women provided information on 2,171 menstrual cycles and serum for measurement of at least one biomarker of ovarian reserve. There were 2,096 cycles from 754 women in the LB cohort, of which 40% experienced LB. After adjusting for age, race, previous miscarriages, and previous pregnancies, diminished ovarian reserve (DOR) was not significantly associated with LB. Low early follicular phase FSH levels increased the odds of LB (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.25-2.71), as did high early follicular phase E2 levels (OR 1.59; 95% CI 1.26-2.01). A total of 608 cycles from 286 women were included in the analysis of luteal phase length, of which 13% had a short luteal phase. After adjusting for age, there was no significant association between DOR and a short luteal phase. The risk of a short luteal phase decreased with increasing inhibin B (OR 0.61; 95% CI 0.45-0.81). Although DOR is not associated with LPD, hormone dysfunction in the early follicular phase may contribute to LPD in women of older reproductive age.

Chronic ethanol drinking increases during the luteal menstrual cycle phase in rhesus monkeys: implication of progesterone and related neurosteroids.

Sporadic reports of alcohol consumption being linked to menstrual cycle phase highlight the need to consider hormonally characterized menstrual cycle phase in understanding the sex-specific effects of risk for alcohol drinking in women. We investigated the association between menstrual cycle phase, characterized by circulating progesterone and menses, with accurate daily alcohol intakes in rhesus monkeys, and the contribution of progesterone derived neuroactive steroids to cycle-related alcohol drinking. Menses (daily) and progesterone (2-3×/week) were obtained in female monkeys (n = 8, 5 ethanol, 3 control) for 12-18months. Ethanol monkeys were then induced to drink ethanol (4% w/v; 3months) and given 22h/day access to ethanol and water for approximately 1year. In selected cycles, a panel of neuroactive steroids were assayed during follicular and luteal phases from pre-ethanol and ethanol exposure. There were minimal to no effects of ethanol on menstrual cycle length, progesterone levels, and follicular or luteal phase length. The monkeys drank more ethanol during the luteal phase, compared to the follicular phase, and ethanol intake was highest in the late luteal phase when progesterone declines rapidly. Two neuroactive steroids were higher during the luteal phase versus the follicular phase, and several neuroactive steroids were higher in the pre- vs. post-ethanol drinking menstrual cycles. This is the first study to show that normal menstrual cycle fluctuations in progesterone, particularly during the late luteal phase, can modulate ethanol intake. Two of 11 neuroactive steroids were selectively associated with the effect of cycle progesterone on ethanol drinking, suggesting possible links to CNS mechanisms of ethanol intake control.

The Relationship Between Progesterone, Sleep, and LH and FSH Secretory Dynamics in Early Postmenarchal Girls.

During puberty, LH pulse frequency increases during sleep; in women, LH pulse frequency slows during sleep in the early/middle follicular phase (FP) of the menstrual cycle. The origin and significance of this developmental transition are unknown. To determine the relationship between progesterone (P4) exposure, sleep-related slowing of LH pulses in the FP, and the intercycle FSH rise, which promotes folliculogenesis, in early postmenarchal girls. 23 girls (gynecologic age 0.4 to 3.5 years) underwent hormone measurements and pelvic ultrasounds during two consecutive cycles and one frequent blood sampling study with concurrent polysomnography during the FP. Subjects demonstrated one of four patterns during cycle 1 that represent a continuum of P4 exposure: ovulatory cycles with normal or short luteal phase lengths or anovulatory cycles ± follicle luteinization. Peak serum P4 and urine pregnanediol (Pd) in cycle 1 were inversely correlated with LH pulse frequency during sleep in the FP of cycle 2 (r = -0.5; P = 0.02 for both). The intercycle FSH rise and folliculogenesis in cycle 2 were maintained after anovulatory cycles without P4 or Pd exposure or nocturnal slowing of LH pulse frequency in the FP. During late puberty, rising P4 levels from follicle luteinization and ovulation may promote a slower LH pulse frequency during sleep in the FP. However, a normal FSH rise and follicle growth can occur in the absence of P4-associated slowing. These studies therefore suggest that an immature LH secretory pattern during sleep is unlikely to contribute to menstrual irregularity in the early postmenarchal years.

PSXIII-40 Monitoring in-line milk progesterone profiles prior to first breeding to predict reproductive performance in Holstein cows.

We investigated if milk progesterone (P4) profiles determined by an in-line milk P4 analysis system (Herd NavigatorTM, DeLaval Inc.) could be used to predict subsequent reproductive performance. Specifically, we evaluated associations of (1) commencement of luteal activity (C-LA), (2) first luteal phase length, (3) first P4 peak, and (4) number of luteal phases prior to first breeding, with pregnancy at first AI (P/1stAI) and cumulative pregnancy by 150 (P/150) d in milk (DIM). Milk P4 concentrations (ng/mL) were measured approximately every 2 d from ~21 DIM until pregnancy in 1,354 lactations (1,190 cows). Variations in P4 were used to define luteal function, such as C-LA, first luteal phase length, and pregnancy. All AI occurred within 5 d of P4 declining below 5 ng/mL. Variables were categorized into quartiles and data analyzed using GLIMMIX and PHREG procedures of SAS. First AI occurred at 70 ± 17 DIM. Overall P/1stAI and P/150 were 25.6 and 62.3%, respectively. Parameters associated with decreased probability of P/1stAI were first luteal phase length ≥ 17 vs. < 17 d (Odds Ratio [OR]: 0.13; P < 0.01), first P4 peak ≤ 17 vs. > 17 ng/mL (OR: 0.13; P < 0.01), and having one vs. two luteal phases prior to first AI (OR: 0.53; P < 0.01). The likelihood of P/150 was increased in cows that had C-LA before 50 than after 50 DIM (Hazard ratio: 0.64; P < 0.01), and in cows that had a first luteal phase ≥ 17 vs. < 17 d long (Hazard ratio: 0.58; P < 0.01). In summary, prolonged first luteal phase (≥ 17 d), low first P4 peak (≤ 17 ng/mL) and having only one luteal phase prior to first breeding reduced P/1stAI. Furthermore, a delayed C-LA (> 50 DIM) and a prolonged first luteal phase reduced likelihood of P/150.

Changes in Concentration of Creatine Kinase, Body Composition and Lipoprotein during Menstrual Cycle

The aim of our study was to establish the dependence of changes in the concentration of creatine kinase, body composition and lipoprotein on the follicular phase and ovulation. The subjects were healthy and physically active women (n = 9) with normal menstrual cycle, whose age was 19—23 years, body weight — 58.2 ± 6.1 kg, height — 168.4 ± 5.6 cm. All the participants had not used oral contraceptives for 6 months and had regular menstrual cycles. Ethical approval was obtained from Kaunas Regional Biomedical Research Ethics Committee (Report Number BE-2-24). Each subject measured her basal body temperature every morning 3 months before the experiment. The basal body temperature increased approximately by 0.3 °C after ovulation, which is sustained throughout the luteal phase. By the basal body temperature we estimated the approximate day of ovulation, and thus the relative length of follicular and luteal phases. We performed two experiments with each participant: in the follicular phase and ovulation. The days of experiment were chosen considering the duration of the menstrual cycle and the ovulation day of each participant. At the beginning of every experiment the body composition values: weight, BMI, body fat mass (%), body fat mass (kg), muscle mass (kg), water amount (kg) were estimated. The samples of 5 ml and 2 ml venum blood were taken toestablish the amount of estradio17β-estradiol, serum total cholesterol, high density lipoprotein cholesterol, triglyceride and creatine kinase concentration. Creatine kinase concentration was measured 24, 48, 72 hours after the load (100 jumps on the vertical jump force plate from a 75 cm stage). After 10—15 min of not intensive warming-up (slow pedaling veloergometer, heart rate 120—130 b / min) 100 jumps on the vertical jump force plate from a 75 cm stage were performed, with the knee joints flexed up to the angle of 90° (hands on loin). Hormonal analysis confirmed that the subjects were in the correct estrogen status, but no significant change was observed in the body composition and triglyceride values over the menstrual cycle. High density lipoprotein cholesterol and serum total cholesterol values significantly differed in ovulation compared to the values in the follicular phase. Due to the small sample size CK concentration did not significantly differ during the menstrual cycle, but the amount of CK concentration was lager in the follicular phase than in ovulation.Keywords: lipoprotein contentration, creatin kinase, body composition, follicular phase, ovulation.

Using in-line milk progesterone data to characterize parameters of luteal activity and their association with fertility in Holstein cows

Our objectives were to characterize parameters of luteal activity based on milk progesterone concentration (P4c) data from before and after artificial insemination (AI) and to evaluate their potential association with fertility in Holstein cows. Records of AI events (n = 4,353) and of milk P4c (n = 158,961) obtained through an in-line milk analysis system (Herd Navigator, DeLaval International, Tumba, Sweden) from 1,891 lactations of 1,423 Holstein cows were evaluated. Milk P4c (ng/mL) were measured every 2.2 ± 1.9 d (mean ± standard deviation) between 23.6 ± 7.3 and 185.3 ± 56.7 d in milk. Variations in milk P4c of consecutive records were used to determine onset of luteal phase (increase in P4c from <5.0 to ≥5.0 ng/mL), luteal phase length (period, in days, of P4c ≥5.0 ng/mL), cessation of luteal phase (decline from ≥5.0 to <5.0 ng/mL, designated as P4c-decline), and pregnancy (AI followed by a luteal phase that remained uninterrupted until 50 d post-AI). The length of the luteal phase preceding AI, the highest P4c (P4c peak) during the luteal phase preceding AI, the lowest P4c preceding AI (P4c pre-AI) that followed a P4c-decline, and the interval between P4c-decline and AI were evaluated, as well as the interval between AI and onset of luteal phase, and P4c at early diestrus (4.5 ± 0.6 d post-AI), mid diestrus (10.0 ± 0.6 d post-AI), and late diestrus (14.1 ± 0.6 d post-AI). Data were analyzed using logistic regressions, and comparisons made based on quartiles and cut-points established by receiver operating characteristic curve analysis. Overall probability of pregnancy was 32.0%. Parameters associated with reduced probability of pregnancy (represented as percentage points decrease in the probability of pregnancy) were (1) luteal phase length >14.4 d (7.6% decrease), (2) P4c peak ≤24.7 ng/mL (4.5% decrease), (3) P4c pre-AI >0.5 ng/mL (5.5% decrease), (4) interval between P4c-decline and AI of >1.6 d (4.0% decrease), (5) interval between AI and onset of luteal phase of <7 or >11 d (9.3 and 12.1% decrease, respectively), and (6) P4c at early diestrus ≤0.7 or >3.5 ng/mL (15.2 and 6.7% decrease, respectively), (7) P4c at mid diestrus ≤12.4 ng/mL (12.5% decrease), and (8) P4c at late diestrus ≤22.7 ng/mL (9.7% decrease). The parameters of luteal activity associated with reduced probability of pregnancy established here could be used as benchmarks while developing recommendations to improve reproductive performance in herds using in-line milk progesterone monitoring.

Predicted luteal phase length has no influence on success of vitrified-warmed blastocyst transfer in natural cycle

BackgroundThis study evaluated the influence of menstrual cycle length, menstrual cycle variability and predicted luteal phase length on the success of vitrified-warmed blastocyst transfer in natural menstrual cycle using progesterone for luteal phase supplementation.MethodsConsecutive women undergoing vitrified-warmed blastocyst transfer in natural menstrual cycle between January 2013 and December 2015 were included in this retrospective study. Patients’ characteristics, clinical data and data about menstrual cycle length in the last year were collected from our database. Predicted luteal phase length (LPL) was defined as the period starting at ovulation (one day after positive urinary LH test) and ending on the last day before predicted menses, based on women’s usual, minimal and maximal menstrual cycle length data. Logistic regression was used to identify the predictors significantly associated with live-birth.ResultsA total of 1195 FETs (frozen-thawed embryo transfers) resulted in 457 (38.24%) clinical pregnancies, 82 (17.94%), miscarriages and 371 live births (31.04%). There were no statistically significant differences in menstrual cycle length, menstrual cycle variability, day of LH surge, day of FET and predicted LPL between FET cycles resulting in live birth and those not resulting in live birth. In the multivariate logistic regression model, only women’s age (OR 0.93, 95% CI: 0.90–0.96), transfer of morphologically optimal blastocysts (OR 2.17, 95% CI: 1.59–2.94) and endometrium thickness (OR 1.10, 95% CI: 1.03–1.17) were important independent prognostic factors for live birth.ConclusionMenstrual cycle length, menstrual cycle variability and predicted LPL do not seem to be an important factor influencing live birth after FET in natural cycles with progesterone supplementation. Results of our study suggest that FET should not be cancelled if LH surge is detected before or after the predicted period in natural cycle with progesterone supplementation.

Menstrual Cycle in Women Who Co-use Marijuana and Tobacco.

Marijuana is the most commonly used illicit drug in the United States and co-use with tobacco is increasing. Preliminary studies have indicated that marijuana may suppress luteinizing hormone (LH) or shorten the luteal phase. Although the literature is mixed, these sex hormones may play a role in smoking cessation outcomes. This secondary subgroup analysis aims to explore the menstrual cycle of females who co-use marijuana and tobacco compared with females who only use tobacco in a sample of tobacco treatment-seeking individuals. Female participants, aged 18 to 50 years, who self-reported regular menstrual cycles and co-use of marijuana and tobacco were matched 1:3 by age to participants who only use tobacco. Length of the follicular and luteal phases was determined using First Response Urine LH tests. Wilcoxon 2-sample t tests were used to determine differences in phase lengths between groups. Thirteen women who co-use marijuana and tobacco, and 39 women who only use tobacco were included in this analysis. Overall, participants were 37.3 ± 8.0 (SD) years of age, mostly Caucasian (67%), and smoked 12.6 ± 5.2 (SD) cigarettes per day. The luteal phase length among participants who co-use marijuana and tobacco (11.4 days ± 2.2 [SD]) was significantly shorter than among participants who only use tobacco (16.8 days ± 11.3 [SD]; P = 0.002). No differences were found in follicular phase length or menstrual cycle length. These data suggest that females who co-use marijuana and tobacco may have a shortened luteal phase in comparison with females who only use tobacco. Further studies are needed to better understand how marijuana use may impact the menstrual cycle and affect smoking outcomes.

FEMALE ATHLETE TRIAD - PROBABLE BUT DIFFICULT TO CONFIRM IN FEMALE ICE HOCKEY PLAYERS

Female hockey players have high energy expenditure and may enter a negative energy balance (EB) without noticeable body composition changes. Menstrual cycle (MC) and luteal phase (LP) length, EB, and bone mineral density (BMD) were tracked over nine months (mean, SD, ±) in 12 ice hockey players (HP; age 21.1 ± 3.4 yrs; height (HT) 165.9 ± 4.6 cm; weight (WT) 64.7± 8.1 kg, body fat percent (BF%) 22.8 ± 3.8%) and 12 non-athlete controls (C; age 21.4 ± 2.8 yrs., HT 169.5 ± 5.5 cm; WT 65.4 ± 5.4 kg; BF% 20.0 ± 3.1%). HP MC (35.8 ± 11.2 days) was longer than C (29.8 ± 4.3 days) and HP LP (10.1 ± 2.1 days) was also longer than C (9.6 ± 2.8 days). Anovulation occurred in 50.0 % of HP versus 39.2 % of C. No group BMD differences were observed in lumbar spine (p = 0.9), hip (p = 0.5), and radial (p = 0.7) sites. A negative EB was identified (HP = -1026.52 ± 450.1; C = -780.00 ± 310.19 kcal / day), yet no significant within-group differences in WT (HP p = 0.7; C p = 0.8), BF % (HP p = 0.97; C p = 0.6), or fat free mass (HP p = 0.6; C p = 0.98) were found over the study duration. Rigorous hockey schedule likely contributed to 28 % completion of the Basal Body Temperature and MC recordings in HP compared to 70 % in C. Both groups entered a state of negative EB, but did not exhibit a BF % change associated with the Female Athlete Triad.

Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold.

Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg·fat-free mass (ffm)·d. We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg ffm·d. Thirty-five sedentary, ovulatory women age 18 to 24 yr (weight, 59.0 ± 0.8 kg; body mass index, 21.8 ± 0.4 kg·m) completed a diet and exercise intervention over three menstrual cycles. Participants were randomized to groups that varied in the magnitude of negative energy balance created by the combination of exercise and energy restriction. Menstrual disturbances were determined using daily urinary estrone-1-glucuronide and pregnanediol glucuronide, midcycle luteinizing hormone, and menstrual calendars. In a secondary analysis, we calculated EA from energy balance data and tested the association of EA with MD. A generalized linear mixed-effects model showed that the likelihood of a MD decreased by 9% for each unit increase in EA (odds ratio, 0.91; 95% confidence interval, 0.84-0.98; P = 0.010). No specific value of EA emerged as a threshold below which MD were induced. When participants were partitioned into EA tertile groups (low EA, 23.4-34.1; n = 11; moderate EA, 34.9-40.7; n = 12, and high EA, 41.2-50.1; n = 12 [kcal·kg ffm·d]), estrone-1-glucuronide (P < 0.001), pregnanediol glucuronide (P < 0.001), and luteal phase length (P = 0.031) decreased significantly, independent of tertile. These findings do not support that a threshold of EA exists below which MD are induced but do suggest that MD increase linearly as EA decreases. Menstrual disturbances can likely be prevented by monitoring EA using a simplified assessment of metabolic status.

Reproductive biology of captive southern hairy-nosed wombats (Lasiorhinus latifrons). Part 1: oestrous cycle characterisation.

Southern hairy-nosed wombats (SHNWs: Lasiorhinus latifrons) do not breed well in captivity. To better understand their reproduction, daily urine samples were collected from nine captive females and analysed for volume (mL), specific gravity and a qualitative index of the number of epithelial cells, then stored at -20°C until samples could be analysed for progesterone metabolites (P4M). The mean oestrous cycle length was 35.1±2.4 days; however, individual cycle length ranged from 23 to 47 days. The mean luteal phase length was 20.8±1.3 days (range: 12 to 33 days). Urinary P4M was divided into four oestrous cycle stages: (1) early follicular phase, (2) late follicular phase, (3) early luteal phase, (4) late luteal phase, and analysed against urinary characteristics. During the late follicular phase, urine volume decreased (P=0.002) while urine specific gravity (P=0.001) and concentration of epithelial cells (P=0.004) both increased. The level of variability in oestrous cycle length suggests that some captive females may exhibit abnormal cycles; however, the changes in the urinary characteristics associated with the different stages of the oestrous cycle appear to offer a possible non-invasive means of monitoring the reproductive status of captive SHNWs.

Relationship Between the Menstrual Cycle and Timing of Ovulation Revealed by New Protocols: Analysis of Data from a Self-Tracking Health App.

BackgroundThere are many mobile phone apps aimed at helping women map their ovulation and menstrual cycles and facilitating successful conception (or avoiding pregnancy). These apps usually ask users to input various biological features and have accumulated the menstrual cycle data of a vast number of women.ObjectiveThe purpose of our study was to clarify how the data obtained from a self-tracking health app for female mobile phone users can be used to improve the accuracy of prediction of the date of next ovulation.MethodsUsing the data of 7043 women who had reliable menstrual and ovulation records out of 8,000,000 users of a mobile phone app of a health care service, we analyzed the relationship between the menstrual cycle length, follicular phase length, and luteal phase length. Then we fitted a linear function to the relationship between the length of the menstrual cycle and timing of ovulation and compared it with the existing calendar-based methods.ResultsThe correlation between the length of the menstrual cycle and the length of the follicular phase was stronger than the correlation between the length of the menstrual cycle and the length of the luteal phase, and there was a positive correlation between the lengths of past and future menstrual cycles. A strong positive correlation was also found between the mean length of past cycles and the length of the follicular phase. The correlation between the mean cycle length and the luteal phase length was also statistically significant. In most of the subjects, our method (ie, the calendar-based method based on the optimized function) outperformed the Ogino method of predicting the next ovulation date. Our method also outperformed the ovulation date prediction method that assumes the middle day of a mean menstrual cycle as the date of the next ovulation.ConclusionsThe large number of subjects allowed us to capture the relationships between the lengths of the menstrual cycle, follicular phase, and luteal phase in more detail than previous studies. We then demonstrated how the present calendar methods could be improved by the better grouping of women. This study suggested that even without integrating various biological metrics, the dataset collected by a self-tracking app can be used to develop formulas that predict the ovulation day when the data are aggregated. Because the method that we developed requires data only on the first day of menstruation, it would be the best option for couples during the early stages of their attempt to have a baby or for those who want to avoid the cost associated with other methods. Moreover, the result will be the baseline for more advanced methods that integrate other biological metrics.

The TOX-OER project: Learning Toxicology through Open Educational Resources. An International experience in permanent education

The objectives of this retrospective study were to use in-line milk progesterone (mP4) data to investigate relationships of (1) commencement of luteal activity (CLA), and (2) luteal phase (LP) length and frequency preceding first postpartum AI, with parity and AI outcomes in Canadian Holstein cows. Starting 21 ± 1 days postpartum (DPP), levels of mP4 were assessed every 2.2 ± 2.0 d through an automated in-line milk analysis system (Herd Navigator™, DeLaval International, Tumba, Sweden) until ∼55 d after first or second AI in 748 Holstein cows from two herds. The CLA was defined as the DPP of the first of at least two consecutive samples with mP4 ≥5 ng/mL, and the period with elevated mP4 (≥5 ng/mL) was defined as the LP. Cows were categorized by CLA [earlier (≤) or later (>) than 28, 35, 42, 49, 56, and 63 DPP], and by the pattern of LP frequency preceding first AI as having or not: (1) one or more normal LP (LP length ≥7 and ≤19 d); (2) one or more abnormal LP (LP length <7 or >19 d, or interluteal period ≥12 d); and (3) two or more LP (either normal or abnormal). Outcomes of first or second AI were determined by the interval between AI and cessation of the ensuing LP as: non-pregnant (mP4-decline ≤30 d), presumed-pregnant (no mP4-decline until 55 d), or presumed-pregnancy loss (mP4-decline between 31 and ≤55 d). The odds of pregnancy per AI (P/AI) at 55 d and pregnancy loss were evaluated using generalized linear mixed models. Primiparous cows had lower odds of having CLA ≤28 DPP [Odds ratio (OR) = 0.58, P = 0.002] and one or more abnormal LP (OR = 0.73, P = 0.04) than multiparous cows. In multiparous cows, CLA ≤28 DPP decreased pregnancy loss (OR = 0.48, P = 0.05) and CLA ≤56 DPP increased P/AI (OR = 4.69, P < 0.01) compared to a later CLA. Primiparous and multiparous cows that had one or more normal LP before first AI had increased P/AI (OR = 3.85 and 3.45, respectively, P < 0.01) and reduced pregnancy loss (OR = 0.26 and 0.27, respectively, P < 0.01) than cows without a normal LP. Primiparous cows that had one or more abnormal LP had decreased P/AI (OR = 0.62, P = 0.04) and increased pregnancy loss (OR = 1.64, P = 0.04) compared to those without an abnormal LP. In summary, AI outcomes were improved in multiparous cows that had early CLA and in cows of both parity groups that had at least one normal LP before first AI. However, primiparous cows that had at least one abnormal LP had reduced AI outcomes. Relationships between early postpartum luteal activity and AI outcomes were inconsistent between primiparous and multiparous cows.

Characterization of hormonal profiles during the luteal phase in regularly menstruating women

To characterize the variability of hormonal profiles during the luteal phase in normal cycles. Observational study. Not applicable. Ninety-nine women contributing 266 menstrual cycles. The women collected first morning urine samples that were analyzed for estrone-3-glucuronide, pregnanediol-3-alpha-glucuronide (PDG), FSH, and LH. The women had serum P tests (twice per cycle) and underwent ultrasonography to identify the day of ovulation. The luteal phase was divided into three parts: the early luteal phase with increasing PDG (luteinization), the midluteal phase with PDG ≥10μg/mg Cr (progestation), and the late luteal phase (luteolysis) when PDG fell below 10μg/mg Cr. Long luteal phases begin with long luteinization processes. The early luteal phase is marked by low PDG and high LH levels. Long luteinization phases were correlated with low E1G and low PDG levels at day 3. The length of the early luteal phase is highly variable between cycles of the same woman. The duration and hormonal levels during the rest of the luteal phase were less correlated with other characteristics of the cycle. The study showed the presence of a prolonged pituitary activity during the luteinization process, which seems to be modulated by an interaction between P and LH. This supports a luteal phase model with three distinct processes: the first is a modulated luteinization process, whereas the second and the third are relatively less modulated processes of progestation and luteolysis.

Relationships among early postpartum luteal activity, parity, and insemination outcomes based on in-line milk progesterone profiles in Canadian Holstein cows

The objectives of this retrospective study were to use in-line milk progesterone (mP4) data to investigate relationships of (1) commencement of luteal activity (CLA), and (2) luteal phase (LP) length and frequency preceding first postpartum AI, with parity and AI outcomes in Canadian Holstein cows. Starting 21 ± 1 days postpartum (DPP), levels of mP4 were assessed every 2.2 ± 2.0 d through an automated in-line milk analysis system (Herd Navigator™, DeLaval International, Tumba, Sweden) until ∼55 d after first or second AI in 748 Holstein cows from two herds. The CLA was defined as the DPP of the first of at least two consecutive samples with mP4 ≥5 ng/mL, and the period with elevated mP4 (≥5 ng/mL) was defined as the LP. Cows were categorized by CLA [earlier (≤) or later (>) than 28, 35, 42, 49, 56, and 63 DPP], and by the pattern of LP frequency preceding first AI as having or not: (1) one or more normal LP (LP length ≥7 and ≤19 d); (2) one or more abnormal LP (LP length <7 or >19 d, or interluteal period ≥12 d); and (3) two or more LP (either normal or abnormal). Outcomes of first or second AI were determined by the interval between AI and cessation of the ensuing LP as: non-pregnant (mP4-decline ≤30 d), presumed-pregnant (no mP4-decline until 55 d), or presumed-pregnancy loss (mP4-decline between 31 and ≤55 d). The odds of pregnancy per AI (P/AI) at 55 d and pregnancy loss were evaluated using generalized linear mixed models. Primiparous cows had lower odds of having CLA ≤28 DPP [Odds ratio (OR) = 0.58, P = 0.002] and one or more abnormal LP (OR = 0.73, P = 0.04) than multiparous cows. In multiparous cows, CLA ≤28 DPP decreased pregnancy loss (OR = 0.48, P = 0.05) and CLA ≤56 DPP increased P/AI (OR = 4.69, P < 0.01) compared to a later CLA. Primiparous and multiparous cows that had one or more normal LP before first AI had increased P/AI (OR = 3.85 and 3.45, respectively, P < 0.01) and reduced pregnancy loss (OR = 0.26 and 0.27, respectively, P < 0.01) than cows without a normal LP. Primiparous cows that had one or more abnormal LP had decreased P/AI (OR = 0.62, P = 0.04) and increased pregnancy loss (OR = 1.64, P = 0.04) compared to those without an abnormal LP. In summary, AI outcomes were improved in multiparous cows that had early CLA and in cows of both parity groups that had at least one normal LP before first AI. However, primiparous cows that had at least one abnormal LP had reduced AI outcomes. Relationships between early postpartum luteal activity and AI outcomes were inconsistent between primiparous and multiparous cows.

Follicular flushing in natural cycle IVF does not affect the luteal phase – a prospective controlled study

In contrast to multifollicular IVF, follicular flushing seems to increase the efficacy of monofollicular IVF treatments such as natural cycle IVF (NC-IVF). However, because follicular flushing causes loss of granulosa cells, it might negatively affect luteal phase length and endocrine function of the luteal body. A prospective cohort Phase II study was performed in 24 women undergoing NC-IVF. Women underwent a reference cycle with human chorionic gonadotrophin-induced ovulation without follicle aspiration and analysis of the length of the luteal phase and luteal concentrations of progesterone and oestradiol. In addition, they underwent a NC-IVF cycle which was performed identically but follicles were aspirated and flushed three times. The luteal phase was shorter in 29.2%, equal in 16.7% and longer in 50.0% of cases following flushing of the follicles. Overall, neither difference in luteal phase length was significant [median duration (interquartile range) in reference cycle: 13 (12; 14.5), IVF (flushing) cycle: 14 (12.5; 14.5), median difference (95% CI): 0.5 (–0.5 to 1.5)] nor median progesterone and oestradiol concentrations. In conclusion, follicular flushing in NC-IVF affects neither the length of the luteal phase nor the luteal phase concentrations of progesterone and oestradiol, questioning the need for luteal phase supplementation.

The influence of age, antral follicle count and diestrous ovulations on estrous cycle characteristics of mares

Reproductive aging must be well understood to optimize the reproductive management of older mares and to predict their reproductive life-span. The objectives of this study were to: 1) examine age-related differences in follicular dynamics, endocrine profiles, and primordial follicle counts, 2) evaluate the influence of antral follicle count (AFC) on age-related changes in follicular parameters, and 3) determine the influence of diestrous ovulations on the estrous cycle. Young (3–8yr; n = 10), middle-aged (9–18 yr; n = 16), and old (>18 yr; n = 19) light horse mares were examined with transrectal ultrasonography to monitor follicular growth over two consecutive estrous cycles. Jugular blood samples were taken and plasma progesterone and FSH concentrations were determined by an enzyme immunoassay and radioimmunoassay, respectively. Both interovulatory intervals and follicular phases were longer and the day of follicle deviation occurred later in aged mares. Furthermore, older mares had a tendency to ovulate smaller follicles. Neither follicular growth rate, the number of ovulations nor the length of luteal phase was influenced by mare age. Interestingly, as mare age increased, mares with low AFC had longer interovulatory intervals and follicular phases than mares with medium or high AFC. In addition, the number of primordial follicles declined with an increase in mare age but varied considerably between mares of the same age. Progesterone concentrations were positively influenced by age, whereas FSH concentrations were not, despite that FSH concentrations appeared higher in aged mares during the follicular phase. Estrous cycles with a diestrous ovulation had a longer interovulatory interval as well as a longer follicular and luteal phase while day of deviation occurred later. Progesterone concentrations were significantly higher on day 14 and 16 in estrous cycles with a diestrous ovulation than without a diestrous ovulation. In conclusion, aging in mares is associated with changes in follicular parameters which in turn are closely linked to differences in antral follicle count suggesting a relationship with ovarian reserve. Therefore, determination of antral follicle counts in aged mares can provide valuable information about the reproductive aging process. Finally, diestrous ovulations have a significant influence on different estrous cycle parameters.

Non-invasive hormonal characterization of the ovarian cycle, pregnancy, and seasonal anestrus of the female addra gazelle (Nanger dama ruficollis)

Non-invasive fecal hormone metabolite monitoring was used to characterize the estrous cycle, pregnancy, and seasonal anestrus of the critically endangered addra gazelle (Nanger dama ruficollis). With less than 250 animals remaining in the wild and ∼168 individuals managed in captivity, it is crucial to maintain sustainable populations. Progestogen and estrogen profiles were obtained from analysis of fecal samples collected approximately every other day, within varying intervals, over the course of 7 years (n = 8 adult females). Average estrous cycle length was 19.5 ± 0.4 days (range, 14–26 days), with a luteal phase length of 14.6 ± 1.2 days (range, 10–16 days), and an inter-luteal period of 5.2 ± 1.4 days (range, 2–7 days). Mean gestation length for six pregnancies was 200.7 ± 0.4 days (range, 200–202 days). Fecal progestogens increased at 12 weeks of gestation and remained elevated until parturition. Addra gazelle females exhibited a period of seasonal anestrus with consistently low progestogen concentrations and no cyclic activity from about September to March. Analysis of reproductive and climate records demonstrated a peak in U.S. births that coincided with maximal rainfall in the native habitat of the addra gazelle. Results show that estrous cycle, luteal phase, and inter-luteal phase lengths in addra are similar to those observed in other gazelle species, however, to our knowledge, this is the first study to demonstrate seasonal anestrus in the Nanger genus.

Prospective evaluation of luteal phase length and natural fertility

To evaluate the impact of a short luteal phase on fecundity. Prospective time-to-pregnancy cohort study. Not applicable. Women trying to conceive, ages 30-44years, without known infertility. Daily diaries, ovulation prediction testing, standardized pregnancy testing. Subsequent cycle fecundity. Included in the analysis were 1,635 cycles from 284 women. A short luteal phase (≤11days including the day of ovulation) occurred in 18% of observed cycles. Mean luteal phase length was 14days. Significantly more women with a short luteal phase were smokers. After adjustment for age, women with a short luteal phase had 0.82 times the odds of pregnancy in the subsequent cycle immediately following the short luteal phase compared with women without a short luteal phase. Women with a short luteal length in the first observed cycle had significantly lower fertility after the first 6months of pregnancy attempt, but at 12months there was no significant difference in cumulative probability of pregnancy. Although an isolated cycle with a short luteal phase may negatively affect short-term fertility, incidence of infertility at 12months was not significantly higher among these women. NCT01028365.